set_property PACKAGE_PIN U18 [get_ports i_clk]
set_property PACKAGE_PIN T19 [get_ports i_uart_rx]
set_property PACKAGE_PIN J15 [get_ports o_uart_tx]
set_property IOSTANDARD LVCMOS33 [get_ports i_clk]
set_property IOSTANDARD LVCMOS33 [get_ports i_uart_rx]
set_property IOSTANDARD LVCMOS33 [get_ports o_uart_tx]
